Conventionally, technique for fixing an electronic element such as a connector to a board is disclosed in, for example, JP-2006-127873 and JP-2009-181785. In the technique, an auxiliary member fixed to the electronic element is inserted into a through hole formed in the board so that the electronic element is fixed to the board. Further, the auxiliary member is soldered to the board, so that the electronic element is solidly fixed to the board.
The auxiliary member such as a connector fixation member described in JP-2006-127873 and JP-2009-181785 has a leg portion to be inserted into the through hole. The leg portion includes a pair of locking parts such as a pair of claws and a pair of first leg portions and another part such as a protrusion and a second leg portion. The pair of locking parts has a latch for latching the leg portion with a periphery of the through hole on a back side of the board. The locking parts are disposed on a top of the leg portion. The other part is different from the locking parts.
The locking parts have a spring or the like, so that the latch is smoothly inserted into the through hole, and the latch is latched on the back side of the board when the elastic deformation of the spring is released. Thus, the electronic element is fixed to the board. This fixation provides temporally joint between the electronic element and the board until the electronic element is mounted on the board, i.e., until a terminal of the electronic element such as the connector is soldered on a corresponding land of the board.
In the conventional auxiliary member, all of multiple leg portions including the pair of the locking parts are inserted into the common through hole. Accordingly, the through hole is an elongated through hole extending along with one direction.
However, when the length of the through hole is large, allowance of an insertion part of the pair of the locking parts to be inserted into the through hole is made large. When the allowance is large, the electronic element may be shaky in an arrangement direction of two locking parts under a condition that the electronic element is temporally jointed to the board. Thus, the electronic element may be displaced along with the arrangement direction of the board, or may be tilted with respect to the board.
Accordingly, when the terminal of the electronic element is an insertion mounting structure type terminal, the terminal may not be inserted into the through hole, or a contact area between the terminal and the solder may be small even when the terminal is inserted into the through hole. When the terminal of the electronic element is a surface mounting structure type terminal, the terminal may be displaced with respect to a corresponding land so that the terminal does not contact the solder, the contact area between the terminal and the solder may be small, or the soldering amount is small since the terminal press contacts the land. Thus, electric connection between the terminal and the land may not be sufficiently secured. Specifically, connection reliability between the terminal and the land may be low.
For example, when the electronic element is tilted with respect to the board, the electronic element may excessively contact a casing of the electronic device in a case where the electronic element is accommodated in the casing. Thus, stress may be applied to a connection part between the terminal and the land.
To reduce the slip of the electronic element, it is preferably to shorten the length of the through hole along with the one direction. When the length of the through hole is small, the allowance of the insertion part of the pair of the locking parts to be inserted into the through hole is made small. Thus, the positioning deviation of the electronic element is reduced under a condition that the electronic element is temporally jointed to the board.
However, when the length of the through hole is shortened, the distance between the latches in the part of the locking parts is also shortened. Thus, the fixation structure of the electronic element with using the auxiliary member may be weak against an external force in the arrangement direction of the insertion part. Specifically, the fixation structure may be weak against twist. Thus, when the terminal is soldered on the land so that the electronic element is mounted on the board, the stress corresponding to the external force may be easily applied to the connection portion between the terminal and the land. Thus, the reliability of the connection portion may be reduced.
Specifically, when the number of terminals is large, the dimensions of the electronic element along with the arrangement direction of the two locking parts, which is parallel to the arrangement direction of the insertion parts to be inserted into the through hole, are large. Accordingly, when the length of the through hole is shortened, the insertion parts are weak against the external force in the arrangement direction. Thus, the connection reliability may be reduced.